15 April 2015, Volume 46 Issue 07

    

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工艺 技术
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  Effect of process parameters on the microstructure and properties of copper film deposited by arc ion plating

  Le-Le DENG;;Bo Hou;;

  . 2015, 46(07): 1-0.

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  Copper films were deposited by pulsed bias arc ion plating technique at different levels of process parameters, such as arc current or negative substrate bias. The influences of arc current and negative substrate bias on microstructure, corrosion resistance performance, and cohesive performance of the copper films were respectively investigated by metallographic microscope, corrosion weight loss test, and bidirectional bend method. The result shows that with the arc current increasing from 40A to 80A, the grain content on the film surface increases obviously, and the large grain size grows from 13.71μm to 19.36μm, meanwhile, the average corrosion rate of copper film decreases. The cohesive performance of copper films increases before decreasing with the increase of arc current, and reaches the top at 60A. With the negative substrate bias increasing, both the grain content and the grain size decrease，while the cohesive performance of copper films increases. The effect of grain purging become considerably obvious when the negative substrate bias reach 200V. When the negative substrate bias is increased from 20V to 180V, the average corrosion rate of copper film decreases first then increases and reaches the best at 140V.
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  Influence of SHMP on ZrO2 Coated on the Surface of the Rutile Titanium Dioxide

  Jing-Wen Wang; long chen;

  . 2015, 46(07): 2-0.

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  Abstract: Taking SHMP as the dispersing agent, we’ve used the method of liquid deposition to coat the ZrO2 on the surface of the rutile titanium dioxide and studied the influence of adding quantity of SHMP on envelope. The structure and performance of the dispersion of the slurry and samples being coated have also been characterized by Zeta-Potential-Analyzer, TEM etc. The results show that the best coating could be got when the quantity of SHMP being added is 1.0% of that of titanium dioxide.
综述 进展
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  Aerogel low-cost preparation and its application in the field of building insulation

  Ya LIAN;;;;

  . 2015, 46(07): 3-0.

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  Because of its unique properties, such as high porosity, low density, high specific surface area, Aerogels have been widely concerned as a new type of nanoporous materials. These excellent properties allow aerogels have extensive application prospects in acoustic impedance coupling, efficient thermal insulation, catalyst, aeronautics and astronautics, etc. In this paper, the low-cost preparation of aerogels and ambient pressure drying technology are studies, and the application status and prospects of aerogels in the field of building thermal insulation are introduced, and the advantages and disadvantages of aerogels compared to mainstream building thermal insulation materials are analyzed.
工艺 技术
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  Study on the foaming process of rigid melamine foam

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  . 2015, 46(07): 4-0.

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  The foaming process is significant to the preparation of rigid melamine foam. Through the ortnhoogal test design, the optimum technologic parameters are as follows. Foaming agent 3%, curing agent 12%, emulsifier 5%, foaming temperature to 120 ℃ for 2 h, then 70 ℃ for 2 h. Analysing the viscosity-temperature curve and DSC of the melamine resin, it can be discovered that the foaming and curing speed matched well. The foam skeleton is thicker and the foam cell is smaller in the condition above , which the SEM also confirmed, makes its compression property better .
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  Study on preparation and modification of WCNT conductive paper

  Zhipeng PANG;

  . 2015, 46(07): 5-0.

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  Abstract Pulp fibers were used as matrix and whisker carbon nanotubes (WCNTs) were used as conductive agent. The WCNT conductive paper was made by traditional paper-making method. The conductive paper were modified by graphitization of WCNTs. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and shielding effectiveness(SE),four-point probes(4PP). The results show that when the incorporating of pulp fibers and WCNTs is 1:1, the conductive paper modified by graphitized WCNTs shows better conductivity and thermal conductivity. In range of 175MHz~2700MHz, the shielding effectiveness of WCNT paper reached to -28~ -35dB and improved 10dB in average.
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  A size-controllable preparation of monodisperse PAA/Fe3O4 magnetic microshperes

  ; Qiang CAI ;;;;

  . 2015, 46(07): 6-0.

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  Monodispersed PAA/Fe3O4 magnetic microspheres with 100-500 nm average sizes were synthesized according to hydrothermal method to overcome the disadvantages of past particles (< 30 nm) which is difficult to get the high saturation magnetization. These microparticles are composed of small primary nanocrystals with a size of 13nm. As the same time, the size of the PAA/Fe3O4 magnetic microspheres can be controlled via altering of the quantity of reagent, the reaction temperature and the reaction time. It shows that with the increase of the microspheres sizes, Ms is increased. Moreover, when the size of PAA/Fe3O4 magnetic microspheres is 490nm, the Ms can be 104.52 emu/g.Finally, the morphologies, magnetic properties had been characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectrometer, vibrating sample magnetometer (VSM).
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  Studies on Hydrothermal Synthesis of Nitrogen-doped Titanium Dioxide with Different Morphologies and Photocatalytic Activities

  ;Yu -Ying ZHENG

  . 2015, 46(07): 7-0.

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  Nitrogen-doped titanium dioxide (N-TiO2) nanopowders were prepared by hydrothermal synthesis in H2SO4, HCl, HNO3 using the titanium nitride (TiN) as both titanium resource and nitrogen resource. Effects of solvent medium and hydrothermal temperature on the crystalline type, morphology, size and the photocatalytic activities of the product was investigated. The SEM, XRD result shows that granular anatase TiO2 is obtained in H2SO4, while rod-like rutile TiO2 could be obtained in HCl and HNO3, the crystalline size is as follows: d(HCl)>d(HNO3)>d(H2SO4), it largens with increasing hydrothermal temperature in the same solvent medium. Nitrogen atoms are doped into TiO2 lattice, form a new bond of O-Ti-N resulting in an increase of the lattice distance, which are confirmed by XPS, HRTEM. The narrow of band-gap and the visible-light response are due to nitrogen doping, which are shown by UV-vis spectra analysis. The experiments of photodegradation of methyl orange show that, the photocatalytic activities is as follows: η(H2SO4)>η(HNO3)>η(HCl), it lessens with increasing hydrothermal temperature in the same solvent medium.
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  Preparation and NO2 sensing of sputtered WO3 thin films

  . 2015, 46(07): 8-0.

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  WO3 thin films with different film densities were deposited under various discharge gas pressures at room temperature using dc reactive magnetron sputtering. Structural characterization shows that the films with a layered structure are composed of monoclinic WO3 nanograins. The film density is decreased with increasing discharge gas pressure. Gas sensors based on WO3 thin films obtain the highest response at 200℃ and show reversible response to NO2 gas at the operating temperature of 50～300℃. The response is increased with decreasing film density under the same conditions.
研究 开发
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  Structural and spectroscopy properties of colloidal Mn:ZnS nanocrystals

  ;Rui-Shi XIE

  . 2015, 46(07): 9-0.

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  Water-soluble Mn:ZnS nanocrystals were successfully synthesized in aqueous solution by a green synthetic route, using mercaptoacetic acid as the ligand, and the doping concentration was tested to explore the effects on structure and optical properties of Mn:ZnS nanocrystals. XRD results show that the obtained Mn:ZnS nanocrystals possess cubic sphalerite structure of ZnS phaseand their average grain size is about 2.1 nm estimated from Scherrer's formula. With the increase of doping concentration, the lattice parameters of the products gradually decrease, which show that Mn ions have been incorporated to the host of ZnS nanocrystals, which is consistent with the EDX results. FT-IR infrared spectrum demonstrates that thioglycolic acid ligand was successfully coated onto the surface of the nanocrystals. Raman spectrum results further confirm that Mn:ZnS nanocrystals have the cubic structure. UV-vis absorption spectra show that the absorption peaks of Mn:ZnS nanocrystals shift to the short-wave direction with the increase of doping concentrations, indicating the decrease of the particle sizes, the average particle size is 2.3 nm with the empirical formula calculation based on the UV-vis absorption spectroscopy results.
工艺 技术
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  Sonochemical Fabrication of Zn5(OH)8Cl2?H2O and Its Conversion into ZnO, Photocatalytic Performance

  Zheng Jun; hou chen;;LI LAI QIANG

  . 2015, 46(07): 10-0.

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  We used zinc powder, CCl4 and pure water with a ratio of 1g：10ml：2ml to synthesize Zn5(OH)8Cl2?H2O nanosheets assisted with ultrasonic irradiation at room temperature. The study describes growth mechanism of Zn5(OH)8Cl2?H2O as well as the evolution into ZnO during calcinations. The morphology and the structure of the Zn5(OH)8Cl2?H2O were characterized by Field Emission Scanning Electron Microscopy (FESEM) and X-ray diffraction analysis (XRD). Its proved high temperature is benefit to the formation of regular ZnO crystals. During photodegradation of methyl orange(20mg/L), it achieved 98.63% at 15min by using Zn5(OH)8Cl2?H2O as photocatalyst, and the degradation efficiency reached 100% at 30min.
研究 开发
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  Effects of H2O2-NaOH on Highly-purification of Porcine-Derived Acellular Dermal Matrix

  Nian-hua DAN

  . 2015, 46(07): 11-0.

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  Using traceable pigskin as raw material, by observing the change of thickness, area, collagen content, non-collagen content in effluent and the histological morphology, the optimum alkali swelling scheme, H2O2 4%-NaOH 6%, of preparing acellular dermal matrix has been harvested. After the preparation of highly-purified porcine-derived acellular dermal matrix, a series of tests have been carried out. The tensile strength of the material was 7.2 Mpa. It has good water absorption ability and no heavy metal. Animal experiments demonstrated no obvious acute peroral toxicity and the cytotoxicity was only I grade. These results lay the foundation for the application of the highly-purified porcine-derived acellular dermal matrix in biomedical materials area in the future with further research.
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  Studies on the ring opening polymerization of 1,4-dioxanone by 2-Hydroxyethanolamine-glycol

  ;Jie WANG;;;Yong-Gang YAN

  . 2015, 46(07): 12-0.

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  poly(1,4-dioxanone) (PPDO) were prepared by the polymerization of 1,4-dioxanone (PDO) without solvent using 2-hydroxyethanolamine-glycol as a non-metallic organic catalyst, which has not previously been reported. The effects of the operating parameters, including the reaction temperature, reaction time and the molar ratio of monomer to catalyst (M/C), on the properties of the synthesized PPDO were systematically investigated. The structure of the products was characterized by 1H NMR, IR and wide-angle X-ray diffraction (WAXD). The intrinsic viscosity ([η]) was measured using a Ubbelohde viscometer. Thermodynamic properties were characterized by differential scanning calorimetry (DSC). The results indicated that the best polymerization conditions were 140°C and 24 hours with M/C equal to 500:1. Furthermore, the results demonstrated that 2-hydroxyethanolamine-glycol is an efficient and easily removed catalyst for the ring-opening polymerization of PDO.
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  First principle calculations on electrical properties effect of Li on Graphene, BC3, C3N surface

  JIA Ying

  . 2015, 46(07): 13-0.

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  The geometrical structures of Li atom adsorption on the most stable sites of pristine and Boron (Nitrogen)-doped concentration for 25% (atom fraction) graphene were optimized by using first principle method based on density functional theory (DFT). The band structures, density of states (DOS), electron transferring, electron density differences and binding energies of both pristine and Boron (Nitrogen)-doped graphene were calculated theoretically. The results revealed that when B-doped concentration which is 25% enhances remarkably the adsorbing energy of Li atom on graphene. But the results suggest that when N-doped concentration which is 25% decreases the adsorbing energy of Li atom on graphene. After Li adsorbed on graphene,BC3 and C3N they all have metal properties.
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  Effect of Environment Polarity on Cementitious Materials Resistance to Sulfate Attack at Low Temperature

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  . 2015, 46(07): 14-0.

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  By means of analyzing the effect of glycerol on Cement-ground limestone cementitious materials resistance to sulfate attack at low temperature（5℃、5% Na2S04），the effect of solvent polarity on thaumasite formation was studied. The results showed that the degree of corrosion of cement-limestone powder specimens aggravated with prolonged, and the corrosion products were mainly thaumasite. The specimens without glycerol fell out at edges and corners obviously, while the glycerol reduced the generation of thaumasite in the corrosion products, and the generation of thaumasite decreased with the increase of glycerol content. The glycerol can reduce the generation of thaumasite in the cement-ground limestone cementitious material, and lowering the polarity of the cementitious Materials environment should improve the cementitious material resistance to thaumasite form of sulfate attack at low temperature.
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  Preparation and tanning properties of the coordination complexes of graphene oxide and trivalent chromiu

  . 2015, 46(07): 15-0.

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  The nanometer sheets dispersion of graphene oxide (GO) was prepared by oxidation and ultrasonication, followed carried out the redox reaction with potassium dichromate and GO in order to synthesize the coordination complexes (GO-Cr(III). The chemical structure and AFM morphology of GO-Cr(III) was characterized by FTIR and AFM. When tanned the leather using GO-Cr(III) tannage contained with 1.0% Cr2O3 and 0.04% GO nanosheets, the shrink temperature of tanned leather reached 115℃ and the adsorption rate of Cr2O3 and GO could reach 95%. The dosages of chrome could reduce 30%~50% compared with traditional chrome tannage. The applied results indicated that the GO-Cr(III) tannage has the advantages of less dosage, excellent tanning effects and higher adsorption rate compare to the traditional chrome tannage, which may be connected with bonding effects and nano effects of GO-Cr(III) and collagen fiber. The research result has positive meaning to tanning leather by using little chrome tannage.
工艺 技术
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  Characterization of microstructure and mechanical property of TiSiCN nanocomposite film deposited by RF magnetron sputtering

  ;Wei LI

  . 2015, 46(07): 16-0.

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  Abstract: Fixing the content of Ti，a series of TiSiCN nanocomposite films with different Si/C ratio were deposited on silicon substrate by RF magnetron sputtering. Using X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), X-ray photoelectronic spectroscopy (XPS) and nano-indentation techniques, the influences of Si/C ratio on microstructure and mechanical property of TiSiCN nanocomposite films were investigated. The results show that, the Si/C ratio has a significant impact on the microstructure and hardness of the films. When the ratio of Si/C content is 2:2, the TiSiCN film is characterized as the nanocomposite structure with TiN nanocrystallites surrounded by the crystallized (SiNx+C) interfacial phase. Due to the coherent growth between TiN nanocrystallites and (SiNx+C) interfacial phase, the hardness of TiSiCN film reaches to 46 GPa.
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  Synthesis and Characterization of Fe3O4/graphene Composites

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  . 2015, 46(07): 17-0.

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  In order to study the relationship between the morphologier of Fe3O4 and the microwave absorption properties of its composites,Fe3O4 nanoparticles/graphene and Fe3O4 nanorod/graphene composites were prepared by hydrothermal method. The structure, morphology and microwave absorption properties of the composites were characterized by XRD, SEM,TEM and vector network analysis (VNA). The results indicated that the Fe3O4 nanorod/graphene composites had better microwave absorption ability than the Fe3O4 nanoparticles/graphene composites. The microwave absorption of Fe3O4 nanorod/graohene values less than -10dB is in the ranges of 9.8-17.9GHz， proving the microwave absorption performance greatly depends on the shape of nanoparticles.
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  Investigation of Catalytic Modification of Light Magnesium Based Hydrogen Storage Material

  Yi-Xin XU

  . 2015, 46(07): 18-0.

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  The purpose of this experiment was to research the influence of TiMn2, TiAl, and Ti on hydrogen storage properties of Mg2FeH6 system, by using of hydrogen storage performance tester and Netzch STA 449F3 thermalanalyser. The results of TPD and isothermal hydrogen desorption test indicate that TiMn2/TiAl/Ti-doped and unalloyed Mg2FeH6 have the similar desorption kinetics of the hydrogen storage. The reaction rate of doped Mg2FeH6 is a little higher, but not much. The above catalyst can decrease the endothermic peak temperature about 27℃. And the catalytic performance of TiMn2 is the best, pure Ti is the better, TiAl is the worst.
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  “Preparation and Characterization of Kaolinite/Alkylimidazole Ionic Liquids Intercalation Composites”

  Xiao-Long DU;

  . 2015, 46(07): 19-0.

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  Abstract: K-[Emim]Br and K-[Bmim]Br were successfully prepared by using K-DMSO and K-MEOH intercalation composites as precursors. The products were characterized by X-ray diffraction (XRD), Thermo gravimetric-differential scanning calorimetry (TG-DSC), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscope (SEM). The XRD results showed that the interlayer d-spacing of kaolinite increased as the result of the successful insertion of ionic liquids, and the d-spacing Δd increased with longer alkyl chain, also concluded that methanol interacted with kaolinite for 5 to 6 days could provide ionic liquids with the optimal intercalated condition. The FTIR spectras suggested that ionic liquids formed hydrogen bonds with the inner surface hydroxyls of kaolinite. The TG-DSC results showed that kaolinite got a better thermal stability due to the increase of the dehydroxylation temperature from 490.6oC to 501.5oC and 495.5oC, respectively. The morphology of products had big changes compared with the raw kaolinite according to the SEM images.
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  Synthesis and Mechanical Properties of Ti2AlC/Al2O3 in situ Composites

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  . 2015, 46(07): 20-0.

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  Ti2AlC/12wt% Al2O3 composite was successfully synthesized from the powder mixture of Ti, TiC, Al and TiO2 by in situ hot-pressing method at 1300 oC. The reaction path and the effect of Al2O3 addition on the microstructure and mechanical properties of the Ti2AlC/12wt% Al2O3 composite were investigated in detail. It is found that the reactions of powder mixture during the hot press sintering contain several intermediate phases, including the formation of Ti-Al intermetallics from Ti and Al, reducing TiO2 by Al to form Al2O3, and reacting of TiAl intermetallics with TiC to form Ti2AlC. Meanwhile, the in situ formed Al2O3 inhibits the abnormal growth of Ti2AlC, and makes the microstrcture possesses fine grains with a uniform dispersion. The Rockwell hardness, compressive, flexural strength and fracture toughness of the Ti2AlC/12 wt% Al2O3 composite are increased by 66%, 126%, 130%, 19.3%, compared to the monolithic Ti2AlC.
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  Preparation of anisotropic bulk (NdDy)11.5Fe81.5Nb1B6 magnets

  Qian SHENYilong Ma ;

  . 2015, 46(07): 21-0.

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  Anisotropic bulk (NdDy)11.5Fe81.5Nb1B6+2wt.%Zn magnets were prepared by applying hot-pressing and hot-deformation . The microstructure of hot-pressed and hot-deformed magnets and effects of different deformation on the microstructure and magnetic properties were studied. The results showed that after Zn addition the magnetic performance of hot-pressed magnets decreased, but that of hot-deformed magnets increased largely, resulting from the formation of good c-axis texture and microstructure. The trend of the magnetic properties and microstructure with the deformation is similar to that of traditional Nd-rich magnets, and that c-axis texture and remanence increased but coercivity decreased. However, the coercivity of hot-deformed magnets increased due to the strong diffusion of Zn during the initial stage of hot-deformation. When the deformation increased to 75%, the performance decreased due to the coarse and uneven grains.
研究 开发
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  Microstructure and mechanical property of laser cladding Co-WC composite coatings on titanium alloy surface

  ;YUAN Zizhou

  . 2015, 46(07): 22-0.

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  The Co-WC composite coatings were fabricated by laser cladding on titanium alloy TC4 surface. Microstructure and mechanical property were studied by scanning electron microscope (SEM), energy dispersive spectrometer(EDS) and sclerometer. The results indicate that the microstructure of the cladding layer of Co+15%WC, Co+30%WC, Co+45%WC and Co+60%WC samples is composed of white strip bulk carbide and branch crystal TiC. The coatings of Co+15%WC, Co+30%WC and Co+45%WC samples are metallurgical bonding with the substrate, and the microstructure of the cladding layers are uniformity and compact without pore and cracking flaws. The coating of Co+60%WC sample is metallurgical bonding with the substrate, however, intraformational cracking happened in cladding layer. Macro rockwell hardness of Co-WC composite coatings fabricated by laser cladding increases by 2~3 times than Ti-6Al-4V substrate, and the value increases more obviously along with the increasing of the content of WC in alloy powder. For four cladding samples from the substrate to the surface of cladding layer, the micro hardness is gradually increasing. Maximum content of WC added in the Co base alloy powder is 45%, when the content is higher than 45%, micro hardness value decreases.
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  Effect of size of Potassium dihydrogen phosphate on properties of Magnesium Potassium Phosphate Cement

  ; Zhen-Yu LAI

  . 2015, 46(07): 23-0.

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  Abstract: As the raw material of potassium-magnesium phosphate cement, KH2PO4 is directly associated with performance of as prepared materials. Effects of KH2PO4 size on setting time, compressive strength, fluidity, adhesive strength, slurry temperature and porosity of the potassium-magnesium phosphate cement are studied in this paper. Results showed that as the KH2PO4 particle size decreases, setting time of potassium-magnesium phosphate cement shortened, fluidity of materials increases and then decreases with minimum particle size in this study , compressive strength and adhesive strength increases with finer KH2PO4, When medium particle size is 45μm, 3h compressive strength of cement is up to 32MPa, 1d adhesive strength is 4.3MPa. Particle sizes of KH2PO4 have significant effects on hydration heat of phosphate potassium magnesium cement. For samples with 100mm×100mm×100mm, central temperature gradually increased, the maximum temperature is up to 79.5℃. As particle size of KH2PO4 was lessen, mean pore size of phosphate potassium magnesium cement reduced and lower porosity also can be gotten. The paper also found that finer particle size of KH2PO4 can significantly reduce "efflorescence" phenomenon of the potassium-magnesium phosphate cement.
综述 进展
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  Progress in electrolyte flame retardant

  . 2015, 46(07): 24-0.

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  The performance, operation mechanism and state-of-the-art of Li-ion battery electrolyte flame retardant additives are being summarized comprehensively in this article, including organic phosphorus flame retardant additives, nitrogen compounds flame retardant additives, halogenated carbonates flame retardant additives, silicone compounds flame retardant additive and composite flame retardant additives. In addition, flame retardant additives and film-forming additives joint using, bifunctional additive are also reviewed in detail. And the effect and mechanism of different kinds of flame retardant additives have been discussed, as well as the influence on the battery. At last, correspondingly outlook of flame retardant additives have been summarized, and some meaningful development directions, such as exploration of bifunctional additive and composite flame retardant additives, are suggested for the next generation of Li-ion batteries electrolyte.
研究 开发
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  Structural，Optical and Electrical Properties of B doped ZnO Films deposited by Low Pressure Chemical Vapor Deposition

  . 2015, 46(07): 25-0.

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  Transparent conductive B doped ZnO (BZO) film grown by low pressure chemical vapor deposition (LPCVD) has been emerging as an efficient light scattering front electrode for thin film silicon solar cells. In the study ,high quality BZO films were grown on glass substrates by LPCVD using Zn(C2H5)2, H2O as precursors and B2H6 as the dopant. The crystalline structure，morphology and electrical properties were characterized by X-ray diffraction (XRD)，field-emitting scanning electron microscope (FE-SEM) and four-probe method. The results show that the thinner films (<500nm) exhibit (002) preferred orientation，while the crystal orientation evolves to (110) with the increase of film thickness.The BZO coated glasses exhibit high transmittance (~80%) in the visible and near-infrared range，and the (110) oriented BZO films present significant diffusive transmittance with the haze (at 550nm) up to 28%.The BZO films with sufficient thickness show good conductivity with sheet resistance down to ~7Ω/sq and resistivity down to ~1.0×10-3Ω?cm.
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  A Study of Hydrophilic and Microstructure of Titanium Dioxide Thin Films Precoated with SiO2

  ;Chao-Yin NIE ;

  . 2015, 46(07): 26-0.

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  The precursor solution of titanium dioxide and silicon dioxide was maded by sol-gel. The multilayer TiO2 thin films with large roughness and porous properties were completed on the normal slide by pre-coating multihole SiO2 , and the surface roughness of TiO2 is 14.7 nm. The solution of TiO2 was investigated by TGA-DSC, the structure and surface morphology of TiO2 films were characterized by X-ray diffraction and scanning electron microscope, scanning probe microscope. The experimental results revealed that the surface of TiO2 films non-precoated SiO2 were smooth, and the others were poly-porous. In the super-hydrophilicity test keeping in the dark, the former was out of super-hydrophilic after 6 hours , while the contact angle of TiO2 films precoated SiO2 kept under 10°after 30 hours. Among the films precoated SiO2 , two layers of TiO2 films showed the excellent property, the contact angle was only 6.7°.
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  Fabrication and nonvolatile memory performance of patterned graphene:polymer composite film

  Chao-Xing WU;

  . 2015, 46(07): 27-0.

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  Resistance memory devices using patterned graphene:polymer as active layer and with ITO (indium tin oxide)/graphene:polymer/Al cross bar sandwich structure were fabricated by spin-coating, lithography and thermal evaporation. The patterned active layer was achieved by using photosensitive polymer as organic matrix. The graphene concentration was optimized to obtain the best rewritable nonvolatile memory effect. The mechanism for the resistance switch effect was also discussed. It was found that the device fabricated with the graphene concentration at 0.01wt% showed not only the best memory performance with a large ON/OFF ratio of 8.9×103, but also satisfactory retention characteristics. Current-voltage analysis suggests that it is the carriers captured and released by graphene that lead to the resistance switch effect.
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  Studies on Preparation and Electrical Properties of PMN-PT/P(VDF-TrFE) Composites

  Jia MENG

  . 2015, 46(07): 28-0.

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  Abstract: Lead magnesium niobate-lead titanate (PMN-PT) ceramic prepared by columbite precursor method and polyvinylidene fluoride-trifluoroethylene P(VDF-TrFE) have been used to fabricate 0-3 composites thick films on ITO substrates by flow casting. The phase structure of PMN-PT was analyzed by XRD and the interface of 0-3 composites was characterized by SEM. Variation of dielectric constant (εr) and electric field applied to the ceramic phase (Ec) with temperature were studied to optimize the polarization temperature. Furthermore, compared with the conventional polarization in stages, PMN-PT ceramic content effect on pyroelectric properties of composites was also discussed under Optimized polarization condition. The results showed that the pyroelectric coefficient increases to 58.6μC·m-2K-1 at a ceramic mass fraction of 55% by polarizing temperature with 110℃.
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  Preparation and Water Retention Characteristics of Modified Montmorillonite with hexadecyl trimethyl ammonium bromide

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  . 2015, 46(07): 29-0.

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  This study was conducted to solve the problem of sand-fixation and moisture retention in desertification region, the montmorillonite was modified by hexadecyl trimethyl ammonium bromide (CTMAB). The water retention property was studied in an artificial climate box with simulating desert climate and the materials were analyzed and characterized by means of SEM, FTIR, XRD and TGA measurements. The results showed that CTMAB had intercalated into the Interlayers of montmorillonite and d(001) layer space Increased from 1.25104nm to 2.09212nm. The organic montmorillonite had excellent water retention property. The clay particles were cemented through the interactions of CTMAB, and the strength and stability of the bonding layer significantly increased. The hydrophobic ends of CTMAB connected to form a hydrophobic network to inhibit the water evaporation. Grass-planting experiment showed that the germination rate of grass seed with organic montmorillonite was significantly improved to 48%, while the rate for control group was only 8%.
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  Self-Assembly of Gold Nanoparticles onto Boron-Doped Diamond Film Electrode and its Electrochemical Properties

  Kai CUI; ;;

  . 2015, 46(07): 30-0.

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  Citrate-coated gold nanoparticles (diameter~18 nm) were absorbed onto Boron-Doped Diamond (BDD) film electrode through a self-assembly process after the BDD film was anodized and animated. By changing the time of AuNPs assembling onto BDD film, we have synthesized AuNPs modified BDD electrode with uniform distribution and high coverage (~30%) of gold nanoparticles. In the system of [Fe(CN)6]3-/4-, we use AC impedance analysis and cyclic voltammetry analysis to research the electrochemical properties of the AuNPs modified BBD. We find that heterogeneous electron transfer rate constant (Kapp) of gold nanoparticle modified BDD electrode increase from 2.8 * 10-4 to 8.9 * 10-4 and the oxidation potential of dopamine reduced from 0.54V to 0.3V, confirming the catalytic effect of gold nanoparticles on the dopamine.
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  Chemical structures and properties of ceramic precursor polysilazanes with different proportion

  Ya-Di TENGXiao-Long SUN;;Yong-Gang SHENG;

  . 2015, 46(07): 31-0.

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  A series of Vinylhydromethylpolysilazanes(PVHMS-r,r=0,20,50,80,100) were prepared from different proportion of dichlorohydromethylsilane and dichloromethylvinylsilane by ammonolysis and thermopolymerization. The polysilazanes have weight-average molecular weights(Mw)of 8.61×104～40.0×104.The structures of the polysilazanes were characterized by FTIR and 1H-NMR. The polysilazanes are amorphous. PVHMS-0 has linear structure, and is soluble in common organic solvents, its residual percentage is 61.8% after pyrolysisin at 1000℃ in N2 and the liquidity increased when it was heated. PVHMS-20 has branched structure, and is not soluble in common organic solvents, the residual percentage is 57.41% after pyrolysis, and it became harden when heated; PVHMS-50 is a linear polymer, containing small amount of rings, and soluble in common organic solvents, the residual percentage is 71.00% after pyrolysis, and soften point is 91℃; PVHMS-80 is a linear polymer containing a small amount of rings, and has solubility in common organic solvents, the residual percentage is 80.81% after pyrolysisin, and soften point is about 140℃；PVHMS-100 has branched structure like tassel，and is soluble in common polar organic solvent solvents，the residual percentage is 85.3% after pyrolysis,and no obvious change was observed when it was heated.
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  Influence of the deposition pressure on the properties of ZnO:Al thin-film produced by r.f. sputtering

  . 2015, 46(07): 32-0.

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  Transparent conductive aluminum-doped zinc oxide ( AZO) films were deposited on glass substrates by RF magnetron sputtering from ZnO:3wt%Al2O3 ceramic target. The films obtained were characterized and analyzed by XRD, SEM, four-point probes, ultraviolet-visible light spectrophotometer. The dependence of argon gas pressure on the structure, morphology, electrical and optical properties were investigated. The argon sputtering pressure was varied between 0.3 and 1.2 Pa. The XRD analysis indicated that AZO films deposited under various argon gas pressures were a polycrystalline wurtzite structure with a [002] preferred orientation. The lowest resistivity was 6.7×10-4 Ω cm (sheet resistance=11.2 Ω/sq. for a thickness=600 nm) which was obtained at an argon sputtering pressure of 0.3 Pa. The average transmittance is over 85% in the visible range for all samples.
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  Effects of K2CO3 on the preparation and optical properties of ZnO nanocrystals doped zinc-alumino-silicate glasses

  Huijun Qin;Alei He;Zhao Gaoling

  . 2015, 46(07): 33-0.

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  In order to investigate the effects of K2CO3 on the preparation and optical properties of ZnO nanocrystals doped zinc-aluminium-silicon (SAZK) glasses, SAZK glasses were prepared by melt-quenching method followed by a heat treatment process. Differential thermal analysis, transmission electronic microscopy, X-ray diffractometer, fourier transform infrared spectrometer and fluorescence spectrophotometer have been used to investigate the microstructure and optical properties of the samples. The results showed that glass ceramics obtained after heat treated at 750 ℃ for 2 h. The main crystal phase in SAZK glasses transformed from Zn2SiO4 to ZnO nanocrystals with increasing K2CO3 content. SAZK glass ceramics showed a wide emission band from 450 to 700 nm with a maximum at 580 nm. The photoluminescence intensity of glass containing 8 mol% K2CO3 in the raw material was strongest.